Can any one please help me identify this object?

I dug up this object with a rototiller on a friend of mines lot that he has owned for 40 years. I believe this is made of marble. It is semi polished. The inside threads are tapered. I have given the dimensions below. Please help.
LENGTH 3.75"
TAPERED WIDTH 2.25" to 1.50"
THREADED HOLE WIDTH .75"
HOLE DEPTH 1.75"
WEIGHT 12oz.

It could be the marble handle of almost anything from an earlier time. Obviously the wooden part has rotted away. I would be looking for other pieces to see if you can't cobble some parts together and then get a better idea of what the greater object is. If you find something else don't forget to mark its location and its distance from the original object. Then you'll get a better idea of the size of the larger object that this marble handle is a part of.

And, yes, it does resemble a cistern pull. I actually looked at some online and they are usually connected to a metal fitting which is connected to a chain. I'd be sweeping the area in your garden with a metal detector. That is if you're still interested. Sometimes it's fun to do these little personal 'anthropology' projects.